This section is intended to introduce the reader to various aspects of art, which may be related to various aspects of the present invention that are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
Satellite television systems, such as DirecTV, have become much more widespread over the past few years. In fact, since the introduction of DirecTV in 1994, more than twelve million American homes have become satellite TV subscribers. Most of these subscribers live in single-family homes where satellite dishes are relatively easy to install and connect. For example, the satellite dish may be installed on the roof of the house.
Many potential subscribers, however, live or temporarily reside in multi-dwelling units (“MDUs”), such as hotels or high-rise apartment buildings. Unfortunately, there are additional challenges involved with providing satellite TV services to the individual dwelling units within an MDU. It may be impractical and/or extremely expensive to provide and connect one satellite dish per dwelling. For example, in a high-rise apartment building with one thousand apartments, it may be impractical to mount one thousand satellite dishes on the roof of the building. Some conventional systems have avoided these issues by converting the digital satellite television signal into an analog signal that can be transmitted via a single coaxial cable to a plurality of dwellings. These systems, however, offer limited channels, have reduced quality compared to all-digital systems, and cannot provide the satellite TV experience to which users who live in single family homes are accustomed.
An alternative solution is to provide a bank of satellites connected to a switch that routes a selected signal to appropriate set top boxes. A 2-way communication between a set top box (or IRD) and the switch selects different antenna configurations. Currently, there are two methods satellite receiver/decoder systems use in such a manner to select different antenna configurations. A standard which encompasses DC level communications and 22 kHz tone communications is set forth in the Eutelsat DiSEqC Bus Functional Specification, Version 4.2 document. The standard is commonly called DiSEqC and allows for two-way transmission of simple information with DC levels or more detailed digital information by use of 22 kHz tones or even PWM modulation of 22 kHz tones. Another method which uses a frequency translation module (FTM), uses a 2.3 MHz, frequency shift key (FSK) modulation scheme to communicate configuration selections.
LNB power supplies employing DiSEqC are required to have a substantial amount of capacitance to ground associated with their outputs. This capacitance tends to distort the 2.3 MHz tone used for communication with FTM satellite antenna switching devices. A system and method that overcomes this problem so that a given IRD can support either approach is desirable.